A process of this type is known from German Patent Specification 3,409,684. This is to be taken as a starting-point, with the proviso that the introduction blades used are made of plastic with metallic guide lamellae, as described in German Patent 3,501,879.
According to this known process, the introduction tool, together with its empty introduction blades, is first inserted a little way into a vertically arranged stator. The coils to be drawn in are then threaded in between the spread tongue tips of the introduction blades fixed in this way. The pushing tool used has radial driving arms which come up against the coil ends with their front side having a radially directed surface or bevelled slightly relative to the radial plane.
It has been shown that, during the drawing-in operation, the coils hanging freely in the introduction blades are subjected to a pressure stress which is always too high. Whilst, on the one hand, the coil sides can be drawn through the narrow gap between the guide lamellae of the tongues of the introduction blades only coil wires are arranged in a generally very flat cross-section, the driving arms of the pushing tool cause a widening or thickening of the copper cross-section of the coil sides, so that a build-up occurs. Because of the thickness of the guide lamellae, even if it is only very small, the actual clear slot width between the guide lamellae is less than the actual groove-slot width. Very high drawing-in forces have therefore been necessary hitherto, especially when a plurality of coils is drawn in simultaneously. Above all, however, damage to the enamel insulation has repeatedly occurred as a result of the high pulling and frictional forces to which the coil wires are exposed.